class_docstr: ImageSet wraps a set of ImageFeature
docstr: Create a ImageSet from rdds of ndarray.
  
  :param image_rdd: a rdd of ndarray, each ndarray should has dimension of 3 or 4 (3D images)
  :param label_rdd: a rdd of ndarray
  :return: a DistributedImageSet
docstr_tok: ["Create","a","ImageSet","from","rdds","of","ndarray",".",":","param","image_rdd",":","a","rdd","of","ndarray",",","each","ndarray","should","has","dimension","of","3","or","4","(","3D","images",")",":","param","label_rdd",":","a","rdd","of","ndarray",":","return",":","a","DistributedImageSet"]
code: def from_rdds(cls, image_rdd, label_rdd=None, bigdl_type="float"):
      """
      Create a ImageSet from rdds of ndarray.
  
      :param image_rdd: a rdd of ndarray, each ndarray should has dimension of 3 or 4 (3D images)
      :param label_rdd: a rdd of ndarray
      :return: a DistributedImageSet
      """
      image_rdd = image_rdd.map(lambda x: JTensor.from_ndarray(x))
      if label_rdd is not None:
          label_rdd = label_rdd.map(lambda x: JTensor.from_ndarray(x))
      return ImageSet(
          jvalue=callZooFunc(
              bigdl_type,
              "createDistributedImageSet",
              image_rdd,
              label_rdd,
          ),
          bigdl_type=bigdl_type,
      )
  
imports: from bigdl.transform.vision.image import ImageFrame
  from bigdl.util.common import *
  from zoo.common.utils import callZooFunc
label_desc: Use image node_id 7 for calling the ImageSet obj's underlying member method code with example usage: obj.from_rdds(cls, image_rdd, label_rdd, bigdl_type) and returns: ImageSet